覆盖YouTube iframe上的div

Question

我想在YouTube iframe上添加一个div，我尝试添加wmode: "transparent"，更改了z-index，似乎没有什么对我有用的任何想法

<div id="ytplayer"></div>
<div id="my_div"></div>

function onYouTubePlayerAPIReady() {
    player = new YT.Player('ytplayer', {
      height: '480',
      width: '853.333333',
      videoId: mMs_XJT6YFc,
      playerVars: {
        wmode: "transparent",
        controls: 0,
        showinfo: 0,
        rel: 0,
        modestbranding: 1,
        iv_load_policy: 3
        },
        events: {
            'onReady': onPlayerReady,
            'onStateChange': onPlayerStateChange
        }
    });
};